I had potted out 4 cucumbers, three in Oasesboxes -self watering pots which consist in a somewhat small vessel for compost (but bigger than that which the cucumbers were in before I potted them on) and a water 'tank' underneath. The fourth is in a 13 (?) inch pot. The Oasesbox ones are all dying.Wilting and turning yellow. Any suggestions? I did wonder if I had overdosed them with iron-based slug bait, but the fourth plant is ok (although it does have more compost) and I am not sure it's that easy to do this anyway.Could it be too much water? It's annoying as it's a bit late to start growing news ones or indeed to buy new plants.

It seems very unlikely to be the iron in the slug bait, I would strongly suggest it's much more likely to be overwatering. When you posted the other day it crossed my mind.

Slug pellets are typically 10g/kg ( in other words 1%) ferric phosphate, which is very approximately a third iron. Soil is 1-5% iron, bagged composts a bit less, maybe 0.3% but it varies. Consequently your pellets are not more iron rich than the soil or compost. Moreover you are not using a thick mulch of them, are you? The instructions say not to and it would be very expensive.

Waterlogging is very problematic for many plants. Essentially it's the lack of gas exchange at the roots and paradoxically the conversion of metal salts like iron and manganese to more soluble reduced forms that cause the problems. Yellowing leaves are a symptom.

Ok I might whip them out of the tanks when I've had my dinner. It may be too late, but it's worth a try. Oasesboxes are officially an expensive mistake, it would seem. I have a trombocini in one which seems ok and a tomato - leaves curling a bit... I am sure they will be good for something. Basil is one thing they cite. Bl**dy expensive basil pots though

I have been experimenting making my own Quadrow this evening. Not that hard but I am not sure it's cost effective. However I won't be ordering any more after the terrible trouble I have had with delivery. (Not the company's fault per se.)

I don't know the Quadgrow system that well, but do use Autopots, which seem similar, in that the pots are sitting in a puddle all the time. They use them at Eden (where I first got the idea) and at Beechgrove, amongst other places. I've used mine for 5-10 years now, works well.

However, the manufacturer is quite keen to point out that the pots need to contain a free-draining mixture. When I bought mine, they recommended 70% soil or compost pus 30% perlite. This suggestion has since modified:-

I use maybe 80/20 HM compost/vermiculite, with a layer of sterile bag compost on top to suppress weeds. The plants didn't get a week to establish but seem to be doing well. I don't put feed into the water, but use various organic feeds from a watering can. I once put organic tomato feed in the reservoir and 'subsequently found out it was based upon fish waste'

Mine have got tomatoes and cucumbers in them. 8 pots. 6 toms of 3 varieties and 2 cucumbers - one burpless, one crystal lemon. In the same greenhouse I've got another 8 terracotta pots sitting in growbag trays, another 6 toms and 2 burpless cues, plus 2 balconniere troughs, with serrano and cayenne chillies. Whilst I'm happy to flood these other trays when we're away, I try to keep them damp rather than wet if possible when we're around.

I think that sort of set up works quite well once the plants get to a reasonable size and the roots are more or less filling the pot ... however small plants struggle when their roots are surrounded by a mass of sodden compost ... if it's possible to water by hand at first and only implement the auto-watering feature once the plants are more robust that would probably help. And as Badger says ... a potting medium with really good drainage is important.

In the Quadgrow system there is a tank of water with a small hold in its lid. You thread a wick though the hole and into a pot which is otherwise separated from the water - the compost is not in direct contact with the water. I have no problem with the Quadgrow system at all, but not sure I have ever used it for anything other than tomatoes.

There main selling points are not watering the plants per se, a constant and consistent supply of plant food and the fact that the tanks hold 30l - you can go away for a week or more and they should be ok. I did have my doubts about Oasesboxes when they arrived, as there's not much room for compost. The receptacle for compost is also cone shaped which makes canes problematic ( the one tom that's in one has a cage.)

All my plants were potted on from 7 inch pots.

I have one tomato in a Grow Pot Tower which is new to me. I doubt it will be ok to leave for a week without watering, but you never know.

I do appreciate mine Herb. Have been watering twice a day over the last 3 weeks. This cuc plant arrived being 6" tall and in 3 weeks it has grown about 3" every day. The pot does not sit in water and it is covered in flowers which I 'prod' with an old toothbrush ! It now has 4 growing stems all supported in various guises in the GH and I think there will be a gazpacho lake later in the summer with the tomatoes and cucs I will have! Please excuse the dirty fingernails I have been digging in the earth this morning.